2014 is definitely the Year of Inequality, judging by the intense media coverage. There is one group, however, that’s been talking about this topic for decades: The Economic Policy Institute, a left-leaning think tank in Washington that’s been producing the invaluable “State of Working America” report every year since 1988.

On Wednesday, the EPI came out with a new report on inequality, in conjunction with a conference the think tank is hosting on Raising America’s Pay. The report relentlessly reviews all of the latest data on pay, wealth and inequality, not to prove for the 1,000th time that inequality is real (it is), but to help us figure out what we can do about restoring the American Dream.

The first conclusion is that raising the wages of American workers is the “core economic challenge of our time,” according to co-authors Josh Bivens, Elise Gould, Larry Mishel and Heidi Shierholz. You can’t fix inequality without fixing stagnant wages, because most Americans get most of their income from what they earn at work.

It used to be that a growing economy helped everyone. The pie got bigger, and everyone got a larger slice. The rising tide did lift all the boats. Workers’ incomes rose, and the poverty rate fell as the economy grew. But something happened between 1970 and 1985 that broke the bond between a higher GDP and a prosperous middle class.

As the above chart shows, the American economy is much more productive than it was in the late 1940s. For decades, workers received their share of the benefits of a more productive work place. From 1948 to 1979, productivity increased 108% while hourly compensation rose nearly as much: 93%. That’s when the middle class was really entrenched. But since 1979, productivity has increased by 65%, while pay only rose 8%.

“Workers are getting a smaller share of the pie that they helped to bake,” said Labor Secretary Thomas Perez in his keynote address at the EPI conference.

What are the causes of weak wage growth? Several factors stand out: Globalization on unfair and unfavorable terms, technological innovation, the failure of the Fed and Congress to aggressively pursue full employment, deregulation of the financial industry, tax and corporate-governance policies that funnel the rewards of success to mostly to top management and shareholders, and the demise of unions and collective action by workers.

What can be done? Raise the federal minimum wage, strengthen workers’ rights to organize, enforce overtime laws and aggressively prosecute companies that steal their workers’ labor and wages. Weaken the dollar and negotiate fair-trade deals. Strengthen the safety net.

And most of all, put full employment and fair pay at the top of the national agenda.